Printing machine



Sept. 30, 1930. w. ROCKSTROH PRINT-ING MACHINE Filed May 9, 1929 Patented Sept. 30, 1930 WALTER ROCKS'I'ROH, F DRESIDEN, GERMANY PRINTING MACHINE Application filed Kay 9, 1929, Serial No. 361,765, and in Germany May 21, 1928.

This invention relates to a device for separating the sheets in printing machines provided with automatic sheet feeding apparatus. The device consists of one or more tilting and rising suction members located at the rear edge of the pile of sheets remote from the impression cylinder. The sheet is tilted and raised by these rear suction members and is released by the suction air being shut off at the rear suction bar. At the same time the sheet is seized by the front suction members which are of a known kind and are mounted on a suction bar and is conveyed over the feeding table to the impression cylinder.

The provisions of suction members at the rear and front edge of the pile of paper has the advantage that the sheets can be separated from one another more rapidly, whereby the number of sheets conveyed per hour is con- 2 siderably incre,ased.

According to the invention, after a sheet has been raised from the pile of sheets by the rear suction member, the following sheet is held in position by movable grippinv members which have a'suction action. The suction members and the gripping members are. controlled by two sets of levers. The suction gripping members are located beyond the edge of the pile of sheets and are only placed on the unraised sheet of the pile of sheets after the suction members have been tilted.

The suction gripping members have the advantage that the uppermost sheet of the pile of sheets is not only held firmly in position but is slightly raised and eased. In the case ofgripping members which have no suction action a pressure is exerted on the pile of sheets, whereby undulations are impressed in .7 the pile of sheets and the raising by suction of the uppermost sheet is detrimentally affected in so far as, when the suction member is subsequently placed on a depression in the sheet, it can not exert a suction action. Through the suction action of the gripping members the impressing of undulations in the pile of sheets is prevented.

A constructional example of the invention is shown in the accompanying drawing, in which raised, as shown in'Fig. 3, place themselves Figs. 1 to 3 show the device in three different positions.

1 is the pile of sheets, on the uppermost sheet 2 of which one or more suction members 3 rest which perform a tilting and raising motion. The tiltin motion is initiated by a cam disc 5 mounted on the shaft 4 (Fig. 1). The cam disc 5 acts on a two-armed lever 7 provided with rollers, which is mounted so as to rotate on a shaft 6 and at the lower end of which a link 8 is pivoted. The link 8 is pivoted at its other end to the lever 9 supporting the suction members 3.

The raising motion is initiated by a cam disc 10.mounte d'on the shaft 4, which acts on a link 11, which is guided in the slots 12 and I 13.

At either end of the shaft 6 a lever 14 is fixed. The two levers 14 are connected together by a loosely journalled tubular member 15, on which the suction gripping members 16 are mounted which are guided by the lever 18 having a roller running in the slotted guide 17. The motionof the suction gripping members 16 is produced by a cam disc 19 mounted on the shaft 4 (Fig. 1), which cam disc acts on the roller of a lever 20 mounted on the shaft 6, whereby the shaftv 6 and the levers 14 have a-rocking motion imparted to them.

In the initial Dositon shown in Fig. 1 the suction gripping members 16 are out of engagement with the pile of-sheets 1. As soon as the suction members 3 have been tilted in accordance with Fig. 2 with the sheet 2 raised by suction, the suction gripping members 16 guided in the slotted guides 17 approach the pile of sheets 1, and after the suction members 3 with the sheet 2 have been under 'thesheet 2 lightly on the following sheet of the pile of sheets 1, so as to keep this sheet in position. Thereupon the suction air is shut ofi at the rear suction bar of the suction members 3 (Fig. 3) so that the sheet 2 can be at the same time seized by the front suction members and be conveyed across the feeding table. to the impression cylinder. The suction gripping members 16 then return into their initial-position (Fig. 1) while the suction members 3 tilt back again and are lowered on to the pile of sheets 1.

What I claim is:

1. A device for separating the sheets in printing machines provided with automatic sheet feeding apparatus, comprising the combination' with suction members capable of being tilted and raised, which are disposed at the rear edge of the pile of sheets remote from the impression cylinder for separating the sheets at the said edge of movable suction gripping members capable of holding the second sheet of the pile after the top sheet has been raised by the suction members, as and for the purpose set forth.

2. J1. device for separating the sheets in printing machines provided with automatic sheet feeding apparatus, comprising the combination with suction members capable of being tilted and raised, which are disposed at the rear edge of the pile of sheets remote from the impression cylinder for separating the sheets at said edge of movable suction gripping members capable of holding the second sheet of the pile after the top sheet has been raised by the suction members, and linkages (7, 8, 9, 11 and 20, 14. 18) for con trolling the said suction members and suction gripping members, as and for the purpose set forth.

In testimony whereof I have signed my name to this specification,

W. ROCKSTROH. 

